Apparatus for adjusting a signal and prohibiting adjustment of the signal based on a position of a movable member

Abstract

A signal adjusting apparatus includes a movable member, a setting device, and a prohibiting device. The movable member is movable in a movable range to have the electrical signal adjusted in accordance with a position of the movable member. The setting device sets a prohibition range in the movable range. The prohibition range is a range where a volume level of the electrical signal is to be constant. The prohibiting device prohibits the volume level from being adjusted under the state that the movable member is located in the prohibition range.

1. A signal adjusting apparatus which adjusts an electrical signal, comprising:
 a movable member which is movable in a movable range to have the electrical signal adjusted in accordance with a position of the movable member; 
 a setting device which sets a prohibition range in the movable range, the prohibition range being a range where a volume level of the electrical signal is to be constant; and 
 a prohibiting device which prohibits the volume level from being adjusted under the state that the movable member is located in the prohibition range, 
 wherein the movable range is composed of a plurality of intervals, which further comprises:
 a first detecting device which detects one of the intervals where the movable member is located, the first detecting device being constituted by a first movable portion mounted on the movable member and a first fixed portion spaced apart from the first movable portion, said one of the intervals being an absolute position of the movable member; 
 a second detecting device which detects a relative position of the movable member within the interval detected by the first detecting device, the second detecting device being constituted by a second movable portion mounted on the movable member and a second fixed portion spaced apart from the second movable portion; and 
 a correction device which corrects the detected relative position based on a relationship between the absolute position and the relative position stored in a memory in advance, 
 an adjusting device which adjusts the electrical signal based on an adjustment state corresponding to the position of the movable member. 
 
 
   
   
     2. The signal adjusting apparatus according to  claim 1 , wherein the first movable portion consists of a plurality of members each of which is formed with a plurality of slits, and wherein the first fixed portion consists of a plurality of optical sensors each of which detects the slits of each of the members. 
   
   
     3. The signal adjusting apparatus according to  claim 2 , wherein the slits of each of the members are arranged to indicate a gray code. 
   
   
     4. The signal adjusting apparatus according to  claim 1 , wherein the second movable portion consists of a member formed with a plurality of slits, and wherein the second fixed portion consists of an optical sensor detecting the slits of the member. 
   
   
     5. The signal adjusting apparatus according to  claim 1 , wherein
 the electrical signal includes a first electrical signal having a characteristic of a volume level and a second electrical signal having another characteristic of a volume level different from the characteristic of the first electrical signal, 
 the adjusting device adjusts the first and second electrical signals, and includes 
 a first unit which sets a first relationship between the output level of the first electrical signal and the position of the movable member, 
 a second unit which sets a second relationship between the output level of the second electrical signal and the position of the movable member, and 
 a third unit which adjusts the output level of each of the first and second electrical signals based on each of the first and second relationships corresponding to the position of the movable member.